The disclosed invention relates to an electrical conduit junction box. In particular, the disclosed invention relates to an electrical conduit junction box that is useful in applications for connecting electrical conduit by facilitating a novel and improved method to transition from in-wall wiring to surface (out of wall) wiring in residential, commercial and industrial building applications. Wiring in such a building is typically installed in conduit located within the walls that exits the wall above the suspended ceiling for connection to other conduits in the electrical distribution system. Traditional electrical conduit junction boxes require the bending of an elbow or offset to the connecting conduit when there is a transition from in-wall wiring to surface wiring in a building. The elbow bend or offset is necessitated because, with a traditional electrical conduit junction box, one box is installed on one side of the wall and the other box is installed on the opposing side of the wall, necessitating the conduit to be bent to travel between the inner side of the wall and the outer side of the wall.
The use of a traditional electrical conduit junction box in applications for a transition from in-wall to surface wiring is labor intensive for both the electrician and the wallboard installer. In such applications, the electrician must bend conduit and then install the junction box and supporting hardware. The wallboard installer must cut a slotted opening for the conduit to exit through the wallboard and then fit the wallboard around the protruding conduit. The disclosed invention eliminates the need for bending of conduit and allows for simplified wallboard installation using a rotary cutter to cut the opening for the electrical conduit junction box.
When using a traditional electrical conduit junction box in transitioning from in-wall to surface wiring, traditional installations are usually performed in one of two ways. In the first traditional installation, conduit is installed from an in-wall device box with a 90 degree bend in the conduit required to exit the wall cavity to connect to a junction box independently supported from the structure (as seen in FIG. 8) per the National Electric Code section 314.23, which requires an enclosure mounted on a building or other surface to be rigidly and securely fastened in place. Performing such an installation with a traditional electrical conduit junction box requires a large opening to be cut into the wallboard that will likely require sealing for fire, smoke or acoustical reasons. Such an installation requires multiple return trips for various distinct contractors, such as electrical contractors, drywall contractors and carpenters, to complete the installation.
In the second traditional installation, conduit is installed from an in-wall device box with an offset bend in the conduit required to exit the wall cavity to connect to a junction box mounted to the wallboard (as seen in FIG. 9). Performing such an installation with a traditional electrical conduit junction box requires a large opening to be cut into the wallboard that will likely require sealing for fire, smoke or acoustical reasons. The surface box cannot be installed until after the wallboard installation. Such an installation requires multiple return trips for various contractors to complete the installation.
What is novel about the disclosed invention is that it's design enables an installation of the disclosed invention which requires no additional mounting brackets or conduit bends as required by the prior art. The disclosed invention is a novel design in which the junction box is installed within and passes thru a wall or wallboard, where said wall or wallboard might be constructed of drywall, dryvit or stucco, wood paneling, plaster and lath (or wire mesh), or any formed finished wall product in a building. Once the junction box is installed in the wallboard, said junction box extends to the interior and to the exterior of that wallboard allowing conduit to be connection both inside and outside of said wallboard. The disclosed invention allows a complete rough-in installation to be finished in a single trip by the electrical contractor and greatly reduces the amount of sealant required for any smoke, fire or acoustical seal resulting in a reduction in installation time that can be as much as 70 percent.
As seen in the prior art, U.S. Pat. No. 8,633,384 B1 demonstrates a telescoping adjustable junction box made to adjust the junction box to be flush with the wall finish after installation of wallboard and finishes, so that a wiring device (e.g., a switch) can be installed therein. The '384 Patent is made for cable or cord installation in the wall cavity only, has no knockouts for conduit entry and is not made to extend past the wall finish. Unlike the '384 Patent, the disclosed invention provides a transition method from in-wall wiring to surface wiring for conduit systems. The disclosed invention is designed to protrude from the wall cavity, permitting connection of conduits located on the surface of the wall to connect with those enclosed within the wall. While a wiring device could, under some circumstances, be installed within the disclosed invention, such as to provide an area to splice wires, the primary purpose is to permit a transition from in-wall wiring to surface wiring which allows for simpler and more cost effective installation.
As further shown by the prior art, U.S. Pat. No. 2,697,535 demonstrates an octagon shaped junction box primarily made for installations in plaster ceilings and designed to provide for conduit entry knockouts spaced in a way to prevent interference between lath channel and conduits entering the junction box. The '535 Patent is designed to mount flush with the finished surface and would primarily be used to support lighting fixtures in a ceiling constructed of lath and plaster.
U.S. Pat. No. 3,701,448 demonstrates a junction box that provides the ability to mount the junction box to corrugated roofing panels. The primary use of the '448 Patent would be for surface mounting only to permit wire splicing or fixture mounting, typically on a ceiling, in which circumstances the positioning of the knockouts reduces the need to bend conduit to enter the junction box.
U.S. Pat. No. 7,165,366 B2 demonstrates a junction box with a shape designed to fit within the corrugations of a roof panel, permitting conduit to be connected without necessitating offsets in the conduit to be bent for surface mounting applications only, typically on a ceiling for wire splicing or fixture mounting. Unlike the '535 Patent, '448 Patent and '366 B2 Patent, the disclosed invention is designed primarily to be used inside walls and provides the ability to transition from in-wall wiring to surface wiring for conduit systems. The knockout placement on the disclosed invention is specifically designed to reduce or eliminate an electrician's need to bend conduit to route it into the disclosed invention.
U.S. Pat. No. 3,724,795 demonstrates a junction box permitting it to be mounted quickly to structural framing members such that the junction box is square to the framing and at a specified depth and therefore flush with the finished wall. Its primary use is the installation of wiring devices to be accessible from a finished wall.
U.S. Pat. No. 6,800,806 B1 demonstrates a junction box designed to enable it to quickly be mounted to the side of a wall stud or floor or ceiling joist where the purpose would be to enable the installation of wiring devices flush with the wall surface. The '806 B1 Patent includes knockouts for conduit and clamps for non-metallic or armor-clad cable permitting a variety of cables and conduits to enter the junction box.
U.S. Pat. No. 7,022,912 B1 demonstrates a junction box that is made for installation in conduit rack systems without the necessity of bending conduit entering the rack system enclosure, the application of which is in the installation of surface mounted or suspended group conduit installation racks where a splice or junction is required.
U.S. Pat. No. 7,554,032 B2 demonstrates a molded electrical junction box with multiple mounting features, the primary purpose of which is to install wiring devices for mounting flush with the wall surface of a finished wall. Unlike the '795 Patent, '806 B1 Patent, '912 B1 Patent, and '032 B2 Patent, the disclosed invention permits an installation which is simpler and more cost effective than the prior art to transition from in-wall wiring to surface wiring for conduit systems and includes side mounting brackets to enable the disclosed invention to be mounted to structural framing members quickly, while maintaining proper alignment depth to other junction boxes in the wall cavity simultaneously with enabling conduit to enter the junction box on the wall surface.
U.S. Pat. No. 5,448,012 demonstrates a method for installing a series of junction boxes with variations of extended depth that permit installation of electrical conduit, in straight sections, between pairs of non-adjacent junction boxes. The primary use of the '012 Patent is installation of wiring devices flush with the wall surface of a finished wall. Unlike the '012 Patent, the disclosed invention is designed to protrude from the wall cavity to permit conduits on the wall surface to be connected with conduits enclosed within the wall, thus providing the ability to transition from in-wall wiring to surface wiring with an installation that is simpler and more cost effective when compared to the prior art.
US 2009/0183891 demonstrates a junction box is a telescoping adjustable box made to adjust the junction box to be flush with the wall finish after installation of wallboard and finishes. This box is made to finish flush with the wall finish, for installation of a wiring device, with no entry provisions outside the wall cavity. Unlike the '012 Patent and 2009.0183891 A1 Patent, the disclosed invention is designed to protrude from the wall cavity to permit conduits on the wall surface to be connected with conduits enclosed within the wall, thus providing the ability to transition from in-wall wiring to surface wiring with an installation that is simpler and more cost effective when compared to the prior art.
U.S. Pat. No. 8,193,444 B2 demonstrates a junction box with a stair stepped back that permits it to be mounted to a framing member or strut to permit conduit to enter the junction box without the need of bending the conduit. The application for the '444 B2 patent is for the installation of wiring devices or splices of wires in surface mounting applications or in applications where wallboard would not be installed over framing members. Unlike the '444 B2 Patent, the disclosed invention permits an installation which is simpler and more cost effective than the prior art to transition from in-wall wiring to surface wiring for conduit systems and includes side mounting brackets to enable the disclosed invention to be mounted to structural framing members quickly, while maintaining proper alignment depth to other junction boxes in the wall cavity simultaneously while enabling conduit to enter the junction box on the wall surface. Additionally, the disclosed invention's full depth provides greater wire capacity and working space.
The prior art in the field does not disclose a junction box which enables transition from an in-wall wiring to surface wiring for conduit systems without the necessity of bending conduit and creating a large wallboard opening at the transition point. The prior art references are either designed to mount flush with the wall surface or do not protrude far enough from the wall surface to accommodate conduit entry on the wall surface. The disclosed invention permits the transition from in-wall wiring to surface wiring in a singular box that is easy to mount, cost effective to use, and reduces or eliminates an electrician's need to bend conduit to enable it to enter the junction box.
Accordingly, a primary object of the disclosed invention is to provide an electrical conduit junction box with a design that extends beyond both sides of the wallboard such that it can be independently supported from the building structure in compliance with the National Electric Code, section 314.23, while facilitating the connection of conduit to the electrical conduit junction box without necessitating the bending or offsetting of such conduit and providing a quick, easy and more efficient means of completing its installation and connection to the building structure and connecting conduit, as well as minimizing the alteration to the wallboard made necessary to properly position the electrical conduit junction box, and thereby reducing the time and material required for sealing gaps in the wallboard surface for fire, smoke or acoustical reasons.